Vehicle controller

Abstract

According to one embodiment, there is provided a vehicle controller including: a sudden change judgment section that judges whether a change rate of a detected yaw rate is equal to or more than a predetermined value; a normative yaw rate calculator that calculates a normative yaw rate based on a steering angle amount; and a correction section that performs a correction for making a detected lateral acceleration close to a value to be detected at a gravity center of a vehicle, by using: the detected yaw rate when the sudden change judgment section judges that the change rate of the detected yaw rate is less than the predetermined value; and the normative yaw rate instead of the detected yaw rate when the sudden change judgment section judges that the change rate of the detected yaw rate is equal to or more than the predetermined value.

The invention claimed is: 
     
       1. A vehicle controller comprising:
 a sudden change judgment section that judges whether a change rate of a detected yaw rate detected by a yaw rate sensor is equal to or more than a predetermined value; 
 a normative yaw rate calculator that calculates a normative yaw rate based on a steering angle amount detected by a steering angle sensor; and 
 a correction section that performs a correction for making a detected lateral acceleration detected by a lateral acceleration sensor close to a value to be detected at a gravity center of a vehicle, the lateral acceleration sensor being positioned not at the gravity center, the correction being performed by using: 
 the detected yaw rate when the sudden change judgment section judges that the change rate of the detected yaw rate is less than the predetermined value; 
 the normative yaw rate instead of the detected yaw rate when the sudden change judgment section judges that the change rate of the detected yaw rate is equal to or more than the predetermined value; and 
 an unstability judgment section that judges that a traveling state of the vehicle is unstable according to a filtered detected yaw rate and the normative yaw rate based on the steering angle amount detected by the steering angle sensor. 
 
     
     
       2. The vehicle controller of  claim 1 , further comprising:
 a vehicle speed calculator that calculates the vehicle speed based on a parameter relating to the vehicle speed, 
 wherein the normative yaw rate calculator calculates the normative yaw rate based on the steering angle amount and the vehicle speed. 
 
     
     
       3. The vehicle controller of  claim 1 ,
 wherein the correction section performs the correction using the normative yaw rate only during a predetermined time and resumes the correction using the detected yaw rate after the predetermined time is elapsed, the predetermined time corresponding to a changing time of the detected yaw rate. 
 
     
     
       4. The vehicle controller of  claim 1 ,
 wherein the unstability judgment section that judges that a traveling state of the vehicle is unstable when a unstable level is more than a threshold value, the unstable level indicating an unstableness of the traveling state of the vehicle, 
 wherein the correction section performs the correction using the normative yaw rate only when the unstability judgment section does not judge the traveling state of the vehicle to be unstable. 
 
     
     
       5. The vehicle controller of  claim 4 ,
 wherein the unstability judgment section makes the judgment by using at least the detected yaw rate and the steering angle amount immediately before when the change rate of the detected yaw rate becomes equal to or more than the predetermined value. 
 
     
     
       6. The vehicle controller of  claim 1 , wherein
 the vehicle controller is capable of performing a vehicle behavior control to suppress a behavior of the vehicle using the detected lateral acceleration subjected to the correction by the correction section. 
 
     
     
       7. The vehicle controller of  claim 1 , wherein the unstability judgment section performs filter processing for a difference between the filtered detected yaw rate and the normative yaw rate so as to obtain an unstable level, and compares the unstable level with a preset threshold value. 
     
     
       8. The vehicle controller of  claim 7 ,
 wherein when the unstable level is more than the threshold value, the unstability judgment section judges that a traveling state is unstable, and 
 wherein when the unstable level is equal to or less than the threshold value, the unstability judgment section judges that the traveling state is stable and outputs a signal to the correction section. 
 
     
     
       9. The vehicle controller of  claim 8 , wherein the unstability judgment makes the judgment at all times by using the detected yaw rate and the normative yaw rate obtained immediately before when a change rate of the detected yaw rate becomes equal to or more than the predetermined value. 
     
     
       10. The vehicle controller of  claim 3 ,
 wherein the sudden change judgment section judges whether a change rate of a crude detected yaw rate which is detected by the yaw rate sensor and not filtered is equal to or more than the predetermined value, and 
 wherein when the change rate of the detected yaw rate is equal to or more than the predetermined value, the sudden change judgment section outputs a sudden change signal. 
 
     
     
       11. The vehicle controller of  claim 10 ,
 wherein a timer sets a predetermined time corresponding to the changing time of the detected yaw rate as a counter value and decrements the counter value gradually upon receiving a sudden change signal, 
 wherein the timer outputs the current counter value to the correction section, and 
 wherein the correction section performs correction for making a detected lateral acceleration output from a filter section close to the value to be detected at the gravity center of the vehicle according to the following correction formula (1)
     Gyc=Gys−Lx ( dγ/dt )+ Lyγ   2   (1),
 
 
 where Gyc is estimated lateral acceleration, 
 Gys is a detected lateral acceleration subjected to filter processing, 
 Lx is a position of the gravity center of the vehicle in a front-back direction with respect to the lateral acceleration sensor, 
 Ly is the position of the gravity center of the vehicle in the left-right direction with respect to the lateral acceleration sensor, and 
 γ is a yaw rate, and 
 wherein Lx is positive when the gravity center GP is located backward with respect to the lateral acceleration sensor, and the Ly is positive when the gravity center GP is located rightward with respect to the lateral acceleration sensor. 
 
     
     
       12. The vehicle controller of  claim 11 ,
 wherein the correction section corrects the detected lateral acceleration Gys with the detected yaw rate when the sudden change judgment section judges that the change rate of a crude (non-filtered) detected yaw rate is less than the predetermined value, and corrects the detected lateral acceleration with the normative yaw rate instead of the detected yaw rate when the sudden change judgment section judges that the change rate of the crude (non-filtered) detected yaw rate is equal to or more than the predetermined value. 
 
     
     
       13. The vehicle controller of  claim 12 ,
 wherein the correction section switches the differential value dγ/dt of the yaw rate in the second term to a differential value of the detected yaw rate or a differential value of the normative yaw rate. 
 
     
     
       14. The vehicle controller of  claim 4 ,
 wherein the correction section includes a selection section, a position correction calculator and a storage section. 
 
     
     
       15. The vehicle controller of  claim 14 ,
 wherein the selection section makes a selection as to whether a differential value of the detected yaw rate or a differential value of the normative yaw rate is used as a differential value for position correction based on a counter value output from a timer. 
 
     
     
       16. The vehicle controller of  claim 14 ,
 wherein the position correction calculator calculates an estimated lateral acceleration by correcting a detected lateral acceleration output from a filter section based on a squared value of the detected yaw rate output from a square calculator. 
 
     
     
       17. A vehicle controller comprising:
 a sudden change judgment section that judges whether a change rate of a detected yaw rate detected by a yaw rate sensor is equal to or more than a predetermined value; 
 a normative yaw rate calculator that calculates a normative yaw rate based on a steering angle amount detected by a steering angle sensor; and 
 a correction section that performs a correction for making a detected lateral acceleration detected by a lateral acceleration sensor close to a value to be detected at a gravity center of a vehicle, the lateral acceleration sensor being positioned not at the gravity center, the correction being performed by using: 
 the detected yaw rate when the sudden change judgment section judges that the change rate of the detected yaw rate is less than the predetermined value; and 
 the normative yaw rate instead of the detected yaw rate when the sudden change judgment section judges that the change rate of the detected yaw rate is equal to or more than the predetermined value, 
 an unstability judgment section that judges that a traveling state of the vehicle is unstable when a unstable level is more than a threshold value, the unstable level indicating an unstableness of the traveling state of the vehicle, 
 wherein the correction section performs the correction using the normative yaw rate only when the unstability judgment section does not judge the traveling state of the vehicle to be unstable, 
 wherein the correction section includes a selection section, a position correction calculator and a storage section, 
 wherein the selection section makes a selection as to whether a differential value of the detected yaw rate or a differential value of the normative yaw rate is used as a differential value for position correction based on a counter value output from a timer, 
 wherein when no signal is received from the unstability judgment section, the selection section selects the differential value of the detected yaw rate and outputs the differential value to the position correction calculator as the position correction differential value. 
 
     
     
       18. The vehicle controller of  claim 17 ,
 wherein the selection section sets the counter value to 0 when a forward movement signal is not received and hence selects the differential value of the detected yaw rate and outputs the differential value to the position correction calculator as the position correction differential value. 
 
     
     
       19. The vehicle controller of  claim 18 ,
 wherein the selection section subjects the selected differential value to a filter processing to prevent sudden change in the difference between a former differential value and a current differential value.